1. Field of the Invention
The present invention relates to an apparatus for towing a workpiece. More particularly, the present invention relates to a motorized tractor-towing apparatus of enhanced stability capable of towing an airplane, trailer, or other workpiece.
2. Description of the Related Art
It is frequently necessary to move closely-parked private aircraft, for example, around an airfield or within a hanger. State of the art devices disclose tractors having some capability of moving such aircraft but are unstable, particularly when pulling a heavy workpiece, such as an aircraft. See, for example, U.S. Pat. Nos. 3,819,001 and 3,861,483. Because of their unstable nature, such prior art devices require a stabilizer bar or other mechanism to stabilize it and make it more maneuverable particularly in a towing attitude. However, such additional structure makes the prior art devices particularly difficult to operate in congested conditions such as those frequently found at private airfields.
Other prior art aircraft handling and towing devices are cumbersome and do not provide for sharp turning radii required in maneuvering aircraft about a congested airfield, for example. See U.S. Pat. Nos. 3,049,253; 2,732,088; 2,734,716; 3,038,550; 3,662,911; 4,318,448; and 4,576,245.
Additionally, there exists the need for an enhanced gripper mechanism to attach to the nosewheel or tailwheel of an aircraft in a secure manner and yet operate with a small turning radius. Prior art disclosures, such as U.S. Pat. Nos. 2,874,861 and 2,877,911, do not permit the type of gripping necessary for a tight turning radius operation with enhanced locking capability.
Accordingly, the need exists for an improved towing apparatus for aircraft and other workpieces which is stable even when not towing a workpiece. However, once engaged to either a nosewheel or a tailwheel of an aircraft for example, the device provides for a tight turning radius and is easy to maneuver in forward or reverse.